A Societally-Optimized Resource Distribution (SORD) Framework for Community Flood Recovery

Abstract

Natural hazards and disasters affect different populations within communities unevenly. However, natural hazards do not have the ability to discriminate between the population of the community; rather, it is the pre-existing socioeconomic conditions and the responses made to the hazards that cause disasters to be inequitable. Despite historical studies showing the disproportionate damages occurring to socially disadvantaged inhabitants, there has been limited studies demonstrating a systematic pursuit of equitable outcomes to natural hazards, particularly related to federal policy. Increasing rates and intensities of natural hazards, coupled with rising urbanization and more expensive infrastructure, underlines the criticality of addressing this shortcoming. A Societally-Optimized Resource Distribution (SORD) framework has been proposed to tackle the issue of socially unjust disasters. The novel framework centers the design of disaster resource distribution around the principles of social justice; equality and equity. Using computational optimization, it is intended that the resource distribution strategies developed through the SORD framework are first and foremost designed for the goal of fairness in the outcomes of a natural hazard. The SORD framework uses six main steps to achieve this goal: 1) hazard identification, 2) choosing societal damage indicators, 3) developing a community portfolio, 4) choosing resource types and amounts, 5) performing optimization, and 6) evaluation and decision-making. In order to demonstrate the SORD framework, an illustrative case study is provided using the 2016 flooding in Lumberton, NC. A community portfolio was developed for Lumberton using post-disaster household and business surveys completed as part of a longitudinal disaster recovery study by the NIST Center for Risk-Based Community Resilience Planning. Through the SORD framework, equality- and equity-based resource distribution strategies were developed and evaluated for the case of riverine flooding caused by the heavy rains of 2016 Hurricane Matthew. Structural retrofits were used as the resources for disaster mitigation, and household dislocation duration and business downtime duration were used as the metrics to gauge societal fairness. Using these metrics, equity was described using an average difference in days of dislocation and downtime amongst households and businesses, respectively, where a lower average difference is more equitable. The evaluations of the retrofit distributions obtained for Lumberton demonstrated that equity-based strategies were desirable compared to those based on equality. Equitable strategies were observed to have greater cost-efficiency not only in increasing equity per $1 million spent, but also in decreasing total days of dislocation and downtime. The high cost-efficiency was achieved with only minimal increases in total days of dislocation and downtime, compared to the equality-based distribution strategies. The results of the case study demonstrate great promise in the current version of the SORD framework. Future work in developing the SORD framework includes providing direction on considering long-term hazards, such as droughts, and non-structural types of resources for disaster mitigation and recovery.